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  <title>ZXing TypeScript | Decoding from camera stream</title>

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    <section class="container" id="demo-content">
      <h1 class="title">Scan 1D/2D Code from Video Camera</h1>

      <p>
        <a class="button-small button-outline" href="../../index.html">HOME 🏡</a>
      </p>

      <p>This example shows how to scan any supported 1D/2D code with ZXing javascript library from the device video
        camera. If more
        than one video input devices are available (for example front and back camera) the example shows how to read
        them and use a select to change the input device.</p>

      <div>
        <a class="button" id="startButton">Start</a>
        <a class="button" id="resetButton">Reset</a>
      </div>

      <div>
        <video id="video" width="300" height="200" style="border: 1px solid gray"></video>
      </div>

      <div id="sourceSelectPanel" style="display:none">
        <label for="sourceSelect">Change video source:</label>
        <select id="sourceSelect" style="max-width:400px">
        </select>
      </div>

      <label>Result:</label>
      <pre><code id="result"></code></pre>

      <p>See the <a href="https://github.com/zxing-js/library/tree/master/docs/examples/multi-camera/">source code</a>
        for this example.</p>
    </section>

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        <p>ZXing TypeScript Demo. Licensed under the <a target="_blank"
            href="https://github.com/zxing-js/library#license" title="MIT">MIT</a>.</p>
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  </main>

  <script type="text/javascript" src="https://unpkg.com/@zxing/library@latest"></script>
  <script type="text/javascript">
    window.addEventListener('load', function () {
      let selectedDeviceId;
      const codeReader = new ZXing.BrowserMultiFormatReader()
      console.log('ZXing code reader initialized')
      codeReader.getVideoInputDevices()
        .then((videoInputDevices) => {
          const sourceSelect = document.getElementById('sourceSelect')
          selectedDeviceId = videoInputDevices[0].deviceId
          if (videoInputDevices.length >= 1) {
            videoInputDevices.forEach((element) => {
              const sourceOption = document.createElement('option')
              sourceOption.text = element.label
              sourceOption.value = element.deviceId
              sourceSelect.appendChild(sourceOption)
            })

            sourceSelect.onchange = () => {
              selectedDeviceId = sourceSelect.value;
            };

            const sourceSelectPanel = document.getElementById('sourceSelectPanel')
            sourceSelectPanel.style.display = 'block'
          }

          document.getElementById('startButton').addEventListener('click', () => {
            codeReader.decodeFromVideoDevice(selectedDeviceId, 'video', (result, err) => {
              if (result) {
                console.log(result)
                document.getElementById('result').textContent = result.text
              }
              if (err && !(err instanceof ZXing.NotFoundException)) {
                console.error(err)
                document.getElementById('result').textContent = err
              }
            })
            console.log(`Started continous decode from camera with id ${selectedDeviceId}`)
          })

          document.getElementById('resetButton').addEventListener('click', () => {
            codeReader.reset()
            document.getElementById('result').textContent = '';
            console.log('Reset.')
          })

        })
        .catch((err) => {
          console.error(err)
        })
    })
  </script>

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